1. Field of the Invention
This invention relates to temporary closure devices suitable for use in tube couplings and also to tube couplings incorporating temporary closure devices.
2. Background Prior Art
U.S. Pat. No. 4,269,237 discloses a device for draining and collecting sump oil from a motor vehicle having a drain plug which is closed by a ball valve or rupturable membrane. Oil is drained from the sump by inserting a drain spigot into the plug body to open the valve or to rupture the membrane so that oil drains through a hose connected to the spigot into a shallow vessel which may be located beneath the vehicle.
British Patent Specification No. 2182320 discloses a keystone bung and a cask connector for beverage casks. The bung has an outer periphery constructed to seal with a given keystone and a through bore closed by a sealing diaphragm. The through bore has an internal screw thread to mate with an external thread on the cask connector so that it can be screwed into the through bore and a tapered inner end of the connector can rupture the diaphragm to open the bung.